THURSDAY, July 31, 2014 (HealthDay News) -- Stress at work may raise your risk of heart attack and stroke, particularly if you work in the service industry or have a blue-collar job, U.S. health officials reported Thursday.

But being unemployed might be just as unhealthy, they added.

"Workplace factors that increase risk include job stress, exposure to air pollution -- like dust and secondhand smoke -- and noise," explained lead researcher Dr. Sara Luckhaupt, from the National Institute for Occupational Safety and Health, part of the U.S. Centers for Disease Control and Prevention.

Some workers may already have other risk factors for stroke and heart attack, such as high blood pressure and cholesterol, which can be made worse by workplace stresses, Luckhaupt explained. In fact, the researchers found that 1.9 percent of workers under 55 reported a history of heart disease and stroke.

"It's probably a combination of personal and work factors," she said.

"Don't forget the job factors," Luckhaupt said. "The noise, the air pollution and job stress could be contributing to the personal risk factors, like difficulty quitting smoking."

Unemployed workers, however, weren't spared, she noted. Among unemployed people looking for work, the rate of heart attack and stroke was also high -- 2.5 percent.

"It may be that the stress of unemployment and the lack of access to health care may be contributing to their health problems," she said.

However, whether these workers have health problems because they are unemployed or if they are unemployed because of health problems isn't known, Luckhaupt said. While the report found an association between employment stress and heart health, it did not prove a cause-and-effect link.

For the study, published in the Aug 1 issue of Morbidity and Mortality Weekly Report, the researchers compiled data from the 2008-2012 National Health Interview Survey.

Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, said, "There is increasing interest in workplace-based disease prevention, health promotion and wellness programs as a means of improving health."

As heart disease and stroke remain the leading causes of death in men and women in the United States, prevention strategies and workplace health programs are essential, he said.

"Health professionals, employers and workers should take proactive steps to improve their heart health, implement and take advantage of comprehensive workplace wellness programs and better utilize effective interventions to prevent heart disease and stroke," he said.